Question

Suppose, in Fig. 26.4a, that the distance between events A and B is 6000 m. The observer is stationed exactly in the middle as shown; however, she does not receive the signals simultaneously. Her detector receives the flash from B 25.0 μs before the flash from A.
(a) Could event B have caused A?
(b) Could B have been the cause of A if the time difference instead was 5.00 μs? Explain the difference between these two situations.